1. Field of the Invention
The present invention relates to a pivoting assembly and, more particularly, to a pivoting assembly for a hand tool foldable to a compact configuration which is excellent for applying high torque to turn objects.
2. Description of the Related Art
A conventional wrench, for example, an Allen wrench, used to grip and turn or twist objects, usually rotary fasteners, such as the head of a bolt, a nut, a pipe, or the like, commonly typically comprises a one-piece L-shaped metal with one end used as the driving stem and the other end used as a handle.
U.S. Pat. No. 5,943,925, Huang, discloses a tool having a foldable structure. The foldable structure disclosed by Hung includes a coupler pivotally coupled between a driving stem and a handle. Applying the foldable structure to the Allen wrench, the driving stem can be folded in parallel with the handle, that is, with a zero angle relative to the handle. This results in a more compact space for storing the tool. In Huang, with respect to the handle, the driving stem can be rotated from an angle of zero degree to an angle of 180 degrees. While turning a fastener in a limited, narrow space, for example, around the boundary of two perpendicularly adjoining planes, the handle of the Allen wrench adopting the foldable structure disclosed by Huang can only be turned between zero degree to 180 degrees along a surface perpendicular to the driving stem. When a half circle of the turning action is complete, the user must disengage the Allen wrench from the fastener. By repositioning the handle to the initial point of the turning action, the turning action is repeated until the fastener is fastened as required. In other words, while tightening or untightening the fastener in a plane with a limited degree of freedom, the user may need to repeat engaging and disengaging the driving stem to reposition the handle. Moreover, using this conventional foldable structure, there is only one end of the wrench that can be used as the driving tool while the other end is used as a handle only. When a different torque is required, or the fastener with a different depth is to be driven thereby, a different driving stem has to be connected and reassembled.
U.S. Pat. No. 6,443,039, Warner, discloses a wrench having two driving stems pivotally connected with each other. One of the driving stems has a female fork joint protruding from a main stem with a hole at the center thereof. The other driving stem has a male connecting joint protruding from the axial center of the main stem. The male joint and the female joint are engaged with each other via a connector such as a roll pin. Therefore, without using an additional hinge or other mechanical coupler, these two driving stems are pivotally connected with each other. One of these two pivotally connected driving stems flips from an angle of about 90 degrees to an angle of about 270 degrees relative to the other.
Therefore, the tool disclosed by Huang and Warner must include holes respectively formed at the two stems. Thus, a pin is inserted through the holes of the two stems to cause the two stems to be pivotally connected with each other. However, the holes formed at the two stems will decrease the strength of the tool so that the tool can not apply high torque to turn objects.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.